- stion 23 Mott Company uses the units-of-activity method in computing depreciation. A new plant asset is purchased for $48,000 that will produce an estimated 100,000 units over its useful life. Estimated salvage value at the end of its useful life is $4,000. What is the depreciation cost per unit? ed out of Select one: a. $.44 b. $.48 c. $4.80 d. $4.40